Diphenyl-substituted semicarbazides



rates f nite nrrnnlvvr-snas'rrrursn sEMicAneAzmus 4 Claims. (Cl. 26i-554) 2 3, 1953, ation Au- The present invention relates to colorstabilizing additives for mineral lubricating oils, which additives areuseful in improving the stability of the oil against color developmenton storage.

in the refining of mineral lubricating oils, it is a goal of theindustry to produce oils having as light a color as possible and, forthis reason, several additional processing steps are often incoiporatedin the refining operation. Although the petroleum industry has been ableto produce light colored oils, it is a known fact that the oilsnevertheless tend to darken upon prolonged storage. The darkening of anoil in storage is very undesirable since consumers greatly prefer lightcolored oils and, as a consequence, the salability of oils which havedarkened in storage is adversely afiected. in order to overcome thetendency of an oil to develop color on storage, the art has for a longtime sought means for improving the color stability of lubricating oils.

It is an object of the invention to provide new chemical compounds whichare useful as additives for preventing color development in a minerallubricating oil.

The present invention is based in part on the discovery that certainderivatives of 4,4-diphenyl semi-carbazide are effective colorstabilizers for mineral lubricating oil. The additives contemplated inthe present invention have the general formula:

wherein R is an alkyl radical containing at least 4 and preferably notmore than about 20 carbon atoms or an aralkyl radical having at least 7and preferably not more than about 22 carbon atoms.

It has been found that lubricating oils containing the additives of theinvention are remarkably stable against color development on storageeven in the presence of a metal catalyst. The concentration of theadditive in the composition should preferably be not less than 0.001% byweight up to the upper limit of solubility, generally not over 2% byweight, with the optimum results being achieved at a concentration ofabout from 0.6 to 1% by weight of the additive based on the weight ofthe mineral lubricating oil.

The mineral oils in which the additives are incorporated may be any oilof lubricating viscosity. Several different oils have been tried rangingfrom motor oils to light machine oils and excellent results have beenobtained with all of these oils.

in the general formula typical radicals which R may represent are butyl,including isobutyl, secondary butyl and tertiary butyl; amyl, includingthe branched chain amyl radicals, hexyl, heptyl, nonyl, decyl, dodecyl,etc. Also such radicals as phenylmethyl, phenylbutyl, phenylamyl,phenylnonyl, phenyldecyl, phenyldodecyl, and other similar radicals, inwhich the alkyl groups may be either straight or branched chain, aresatisfactory.

The additives can be prepared starting from 4,4-dipheuyl semicarbazideby reacting the starting compound with an aldehyde to produce analdehyde semicarbazone. The aldehyde semicarbazone is then reacted withthe appropriate Grignard reagent to produce the particular semicarbazidederivative that is desired.

The addition of the additive to the mineral lubricating oil can beefiected by dissolving the desired amount of additive in the lubricatingoil and the solution of the additive can be accelerated by warming themineral oil slightly.

The following preparations illustrate the preparation of severaladditives which can be used in the present invention.

PREPARATION A l--( l-Pnan 'lLNONYL 4,4-DIPHENYL SEMICARBAZIDE late areaction vessel there was placed 55.6 g. (6.2446 mol) of 4,4-diphenylsemicarbazide and 24.6 g. (0.2446 mol) of hydrochloric acid in alcoholsolution. The resulting mixture was stirred and then allowed to standuntil the hydrochloride salt had time to form and precipitate. There wasobtained by filtration 20 g. of a wet precipitate. The wet precipitateand 40 g. of sodium acetate ($1.5 mol) as a butler were then added to asolution of 25.68 g. (0.2446 mol) of benzaldehyde in 200 ml. of alcohol.The mixture was stirred vigorously and then placed in a beaker ofboiling Water and after the boiling water cooled, the mixture was thenplaced into a beaker of ice. When precipitation was complete, theresultant benzaldehyde semicarbazone was filtered, washed with water,and dried overnight in a vacuum drying tube. The yield was 63.15 g.which is about 81.37% of the theoretical yield.

The 63.15 g. of benzaldehyde semicarbazone was then placed in a secondvessel under an atmosphere of nitrogen and 300 ml. of anhydrous ethylether was added. Thereafter, 108.8 g. of octyl magnesium bromide wasadded dropwise with constant stirring and after standing for one hour,300 m1. of distilled water was added dropwise with stirring in order tohydrolyze the excess octyl magnesium bromide. After an excess of waterhad been added, the mixture separated into two phases and the waterlayer was extracted with additional ether. The other layer resultingfrom this extraction was then evaporated to dryness to obtain a higherboiling liquid layer comprising the final product. The oily product wasidentified as 1-(l-phenylnonyl)4,4-diphenyl semicarbazide. Therefractive index of the product was 1.5459.

PREPARATION B l-( l-PnEnYLnnxYL) 4-,4-nrPnEm L SEMICARBAZIDE A slurryconsisting of 64.5 g. of benzaldehyde 4,4-diphenyl semicarbazone and 200ml. of anhydrous ethyl ether was formed in a reaction vessel equippedwith a stirrer, reflux condenser and a dropping funnel. After fillingthe flask with nitrogen, there was added 100.3 g. of amyl magnesiumbromide dropwise over a period of about four hours. The reaction mixturewas then allowed to stand overnight and there was then added 200 ml. ofdistilled water to hydrolyze the excess of amyl magnesium bromide. Afteran excess of water had been added the mixture separated into two layersand the ether layer. was evaporated to obtain a higher boiling liquidlayer comprising the final product which was identified as 1-(l-phenylhexyl)4,4-diphenyl semicarbazide. This oily liquid had arefractive index of 1.5631. The yield was 81.5 of the theoretical.

Chemical analysis of the product was as follows:

PREPARATION C 1-SECONDARY 'BUTYL-4,4-DIPHENYL SEMICARBAZIDE There wasplaced in a reaction vessel a solution of g. (0.066 mol) of diphenylsemicarbazide in alcohol.

trate the invention and its attendant advantages:

Examples 1 through 7 A number of compositions within the scope of theinvention were prepared by dissolving different additives in varyingamounts in several different samples of mineral lubricating oil. Thesamples were then subjected to an accelerated storage test. In this testa ml. sample of oil was placed in an open ml. container and thecontainer was placed in a circulating hot air oven at a temperature of210 F. and allowed to remain there for hours. By measuring the opticaldensity of the oil before and after the test with a Colemanspectrophotometer, the color stability of the oil was determined. Theoils used in these examples were either a straight paraflin distillateor a fraction of the straight paraffin distillate. The paraflindistillate used in theexamples is a wide boiling range oil having aviscosity of about'95 S. S. U. at 100 F. The remaining oils are narrowfractions of the paraffin distillate having viscosities as follows:

0 6.6 g. of 37% hydrochloric acid (0.066 mol) was then 22;? added andthe mixture was stirred vigorously until the b gg 1i 0 woo hydrochloridesalt had precipitated. The precipitate was 'Zone 5 2 1 0 F- recovered byfiltration. In a separate reaction vessel there was placed a solution ofpropionaldehyde dissolved in 240 ml. of ethyl alcohol. Twenty-four grams(24 g.) The results-of these examples are summarized in the folof thewet precipitate and 36 g. of sodium acetate buffer lowing table:

TABLE I Concentration Optical Density i Additive on Wt. M01. InitialFinalWlth Without Percent Percent Additive Additive 1l-(l-phenylnonyl)4,4diphenyl 1.05 0.8 Paratl'm Dis- 2.0 18.2 28.2

semicarbazide. tillate. .2 1-(l-phenyIn0nyl)4,4-dipheny1 2.10 1.6Paraffin 1315- 2.0 37.1 28.2

semicarbazide. tillate. 3 1-(1-pheny1hexyl)4,4-diphenyl 0.92 0.8Paratfin DlS- 5.5 13.7 49.8

semicarbazide. tillate. 4 l-(l-phenylhexyl)4,4-diphenyl 1.84 1.6Paraffin DlS- 5.5 20.0 49.8

semicarhazide. tilrate. ?5 '1-(1-phenylhexyl)4,4-diphenyl 0.01 0.009Torch Paraf- .2 8.5 23.1

semicarbazide. fin 6 l-secondary hutyl-4;4-diphenyl 0.64 0.8 PararunDis- 5.5 11.3 49.8

semicarbazide. tillate. I 7 l-seeondary butylAA-diplienyl 1.28 1.6Paralfin 1318- 5.5 29.8 49.8

semicarbazide. tnlate.

Initial Optical 'Density Measurements Nude on Sample Without Additive.

were-added. Themixture was then shaken vigorously and was placed in acontainer of boiling water and allowed to remain there until the waterhad cooled. The mixture was then cooled in ice until crystallization wascomplete and the crystalline product was filtered and dried in a vacuumdryingapparatus overnight. There was obtained 8.9 g. of propionaldehyde4,4-diphenyl semicarbazone which represented 50.2% of the theoreticalyield.

The propionaldehyde 4,4-diphenyl semicarbazone then placed in .aseparate reaction vessel and slurried in dry ether under nitrogenatmosphere. One hundred thirty milliters ml.) of methyl magnesiumbromide was then added dropwise from a dropping funnel and when thereaction was complete, the mixture was hydrolyzed with water to form thesemicarbazide. This resulted in the formation of two layers, an etherlayer and .a .water layer, whichxwere separated by decantation and theether layer was evaporated to yield 5.3 ,g. of product. The

It is evident from the data that the compositions of the inventiondemonstrate a marked improvement in color stability.

The only example in which no improvement was noted is Example 2 and inthis example the concentration of additive exceeded the optimumconcentration for the particular oil used therein.

Examples 8 through 20 TABLE II Concentration Optical Density ExfipleAdditive on I .ss... nets.

1- ggilgngalfinigl) 4,4-diphenyl 0. 5 0. 4 Torch Paraffin 3. 5 17. 5 144l-ggolgrriggclyl)4,4-dlphenyl 0. 1 0. 08 Torch iarafiin 3. 5 38. 1441-gtglgnggfiadiyl)4,4-diphenyl 0.05 0. 04 Torch Pnraflfin 3. 106 1441-giilgnggeiiyl)4,4-dlphenyl 0. 92 0. 8 Pigfigil; Dis- 5. 5 15. 7 165l-ggliggrrlgilziieiiyl) 4,4-dipheny1 0. 92 0. 8 Dagpnd Par- 5. 8 14. 7200+ l-ggglilgiriggelryl) 4,4-diphenyl 0. 92 0.8 Zone Pareflim. 19. 752. 0 200+ 1-ggflgnggeliyl)4,4-dlphenyl 0. 92 0.8 Pegging Dlsl9. 8 58. 8200+ l-gtlahpggnglziieiiyl) 4,4-d1phenyl 0. 92 0. 8 Torch Parafiln 2. 222. 8 200+ l-glghceanglzaleizyl)4,4-dlphenyl 0.92 0.8 Farsi:- Dis- 28.117. 5 200+ l-(s-lplliiganryiafighg 4-dlphenyl 0. 92 0.8 Straw Paraffin.ll. 9 14. 4 200+ l-gglpihcgirigsllziieyl)4,4-d1phenyl 0.92 0.8Pafirfiglgi' Dis- 4. 2 20. 6 200+ l-gllpiheanggeixeyl) 4,4-dlpheny1 0.092 0. 08 1??321; Dis- 4. 2 21. 0 200+l-sseefiziigagyazlggtylAA-dlphenyl 0. 64 0. 8 Paris: Dis- 5. 5 14.2 165Initial Optical Density Measurements Made on Sample Without Additive.

Again the data shows the marked improvement in wherein R is selectedfrom the group consisting of alkyl color stability which is possessed bythe compositions of radicals having from 4 to about carbon atoms andthis invention. From the examples it is also apparent aralkyl radicalshaving from 7 to about 22 carbon atoms. that the additives are effectiveover a fairly wide range 1-(l-phenyln yl) ,4- ip yl a a ideofconcentration. 3. 1-(l-phenylhexyl)4,4-diphenylsemicarbazide.

It is intended to cover all changes and modifications 4. l-secondarybntyl-4,4-diphenyl semicarbazide.

in the examples of this invention herein given for purposes ofdisclosure which do not constitute departure No references Citedfrom thespirit and scope of the appended claims.

This application is a division of my application Serial Number 381,975,filed September 23, 1953.

I claim:

1. Compounds having the formula,

i i i R-N-N-0-

1. COMPOUNDS HAVING THE FORMULA,